An Intersection, Briefly

By Hea-Ream Lee

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A Life of Science: A Series by New Scientists

It’s hard not to want to make some kind of cosmic assumption about improbable intersections.

I move quickly through the ‘50s, watching the decade fly by through the lens of my microscope, the plastic eyepiece warming against the skin around my eyes. The ‘60s are a little trickier, the dark stripes coming more quickly now. I slide the core sample, taken from a piñon pine in the forests of Arizona, until the tip of my pencil is visible in the viewfinder. I see the wood and graphite chipping off the point, like avalanches down a chiseled onyx mountain.

The Carson Scholars program at the University of Arizona is dedicated to training the next generation of environmental researchers in the art of public communication, from writing to speaking. Partnering with, the program will present essays and other writing from students and alumni of the Carson Scholars Program—A Life of Science—with hopes of inspiring readers to understand not only research findings but the textures of the lives of scientists and others engaged in the crucial work of helping the planet along in an age of unprecedented change.

I’m here in the Laboratory of Tree-Ring Research at the University of Arizona because I’m a writer. Before that, I studied plants and worked in labs, and now I write about the intersections of those two worlds. I’m here because I want to date tree rings, learn something new about the world, and turn that bodily experience into words.

The sample, a slim cylindrical cross-section through the tree’s center, sits on a platform set up underneath a microscope. I can slide the platform side to side by turning a small silver crank, which will move the platform and the sample several micrometers at a time. I operate it with the tip of my index finger—sliding frictionless through decades of the tree’s history with the flick of a digit.

I line up the ring border with the crosshair and push a button on a small box, and a beep is emitted. Then I turn the crank until the crosshair now intersects the next ring border, and push the button again. I hear another little beep, glance at the computer and see that the once-empty spreadsheet cell has been filled with a number. The width in micrometers of the growth ring, the measure of a year. A representation of a season of rain, sun, foraging animals, sweatered leaf-peepers, burrowing insects, acid rain, blustery wind, and silence. A year translated into a collection of cells, translated into a number.


In 1996:

I am three years old and live on the Japanese island of Kyushu, a small city near Fukuoka. My dad is working as a postdoc at the university, building ocean models.

Comet Hyakutake is discovered by an amateur astronomer on the same island where my family lives. Yuji Hyakutake has been searching for comets for seven years, even moving his family from Fukuoka to Kyushu in search of clearer skies. He stands on a mountaintop in the village of Hayato, the blueblack sky before him, no ceiling on the dawn, and trains his binoculars, a giant pair of 43-pound Fujinon 25x150s, on the sky. They click against his gold-rimmed glasses. He breathes. And suddenly, an enormous, electric blue streak. Later that year he will tell an interviewer: “I said to myself, ‘I must be dreaming.’” It is nicknamed the Great Comet of 1996, small but bright with an enormous tail, the longest one ever recorded. It burns iridescent aquamarine as it slinks past the Earth.

The Southwest suffers from a severe drought. Wheat crops in New Mexico are almost completely decimated. Their plump plaited tips shrivel into commas and blow away, their tall stalks limpid and delicate, swooning gently to the ground. Riverbeds remain arid, no rushing flood of rain to dislodge the dented Coke cans and animal bones. Trees are stressed by the lack of rain and high heat, growing more slowly, conserving their cellular energy for survival. The drought is estimated to cost the state of Texas over $5 billion.


The author in Kyushu, 1996
The author in Kyushu, Japan, 1996.
Photo courtesy Hea-Ream Lee.

Alex, who has been working in the lab for years, teaches me how to date a tree core: take a sample and, based on nothing but counting and patterns and a few slips of graph paper, figure out when it germinated and when it was cut down. We make a skeleton plot, a graph that shows the position and magnitude of the narrow rings in a core sample. If the fourth and seventh rings are narrower than the ones around them, for example, I draw two lines on a long strip of graph paper, at the fourth and seventh notches. The length of these lines correspond to the narrowness of the rings. Once I have several skeleton plots sketched out on strips of paper, I line them up, sliding them back and forth, trying to find the best fit.

Ideally the lines should match in all of the skeleton plots, because the trees all experienced droughts in the same years, leading to narrow rings of the same magnitude in the same years. And of course this is not how it ends up working out—the trees might not come from the same subplot, or are subject to individual variation, or are simply finicky that way.

An Introduction to Tree-Ring Dating, on fit: “While several patterns match, there are many individual rings which do not match from plot to plot. This variation is typical. It is logical to ask how many such unmatched rings can be accepted in what we call matched plots. Our answer would have to be that, when most of the rings match, the fit is considered correct. While this may sound like a very unscientific answer, experienced dendrochronologists using these methods are able to duplicate each other.” It’s an art, a form of association, a matter of seeing patterns.

It makes me feel powerful. Assigning these trees a place in history, plucking their stories out of the unmarked ether and pinning them to a timeline that we know and understand. And it also feels wrong, disturbing. Disorienting to be assisting in the creation of a record that exists in the realm of human understanding, when it feels like a timeline that shouldn’t be assembled or understood by people.


One day in the lab Alex showed me the Prometheus tree, a section of what at the time had been the oldest known living organism on earth. It was over 5,000 years old when it was cut down in the 1960s by a grad student. Prometheus is older than the pyramids of Giza, older than Stonehenge, older than the epic of Gilgamesh. I stared up at the gnarled section, mounted and hung in a prominent position in the lab, then went home and lay in bed. Later I went to the grocery store. After that I filled up my car with gas. I talked to my professor about the essay and she told me that the movement of scale is existentially troubling. It’s too much. I thought about the comet and the man who saw the comet, the amount of time that the comet will exist, how the comet will outlive the man, will outlive me, will probably never pass by Earth again. I thought about how if it weren’t for that grad student who cut it down, Prometheus might still exist on Nevada’s Wheeler Peak, twisted and bare, more sculpture than living organism.


In 2002:

I am nine years old. My family has relocated to Princeton, New Jersey, and I exist in its idyllic suburban comfort, wandering amidst its stately homes, its gothic chapels.

The average temperature in Tucson, Arizona in June is 105 degrees F. It does not rain at all in April, May, or June.

In 2002 Yuji Hyakutake dies of a brain aneurysm. NASA memorializes him on their Comet Hyakutake website with a quote: “I don’t care about the naming of the comet. If many people could enjoy the comet, that is the happiest thing for me.”


Comet Hyakutake
Comet Hyakutake (Comet C/1996 B2), viewed on March 25, 1996 from the Johannes-Kepler Observatory in Linz, Austria.
Photo by E. Kolmhofer and H. Raab, courtesy Wikimedia.

In 2019:

I will learn that the Southwest has been in what some consider a superdrought for the last 20 or 30 years. I will learn that 2002 was so dry a growing season that dendrochronologists use it as a clear marker, an easy date to hang their tree ring timelines on because most trees in the area put on extremely narrow rings—or none at all.

I will slide my finger over a core sample, a striated sliver of wood, and see where one ring is separated from the next by a dark band of latewood, touch the precise spot where 2000 turns into 2001, then jumps to 2003. I marvel over the absence of a ring, of growth, of a year.

As I practice tree ring dating I come to expect certain years to correspond to narrow rings: 1996, 2002, 2011. Years in which droughts restricted growth in trees in the Southwest. Another telltale pattern: the Flagstaff Signal, discovered by the father of dendrochronology, A. E. Douglass, who founded the Tree-Ring Lab in which I learn these skills.

Alex pulls up the metadata for a sample I’ve recently dated on the computer, seeking another pattern. A field of black, a stark blue line, jagged mountains and valleys representing ring widths. We scroll backwards to find the right time frame and like magic, it’s there: sharp downwards peaks at 1899, 1902, and 1904.

It feels like a triumph, nature working as it should, an outcome that helps prove the theory. I think about hundreds of thousands of jagged mountain ranges piled on top of each other, their valleys varied in depth, but all pointing to a kind of consensus; a joined history of trauma, a single timeline, a chorus of voices singing the same song.


In 2011:

I sit on the beach with my friend Janet. We are 18 and have just graduated high school and think we are hot shit. It is a grey day at the shore, though warm. The salt gets in our hair and gums up our skin and everything looks like it’s been filmed through a lens that’s been thoroughly handled by a sticky toddler. We talk about how we never want to have kids, and I wear my mom’s grey cardigan over my bright blue bikini. We are excited about college. Janet pulls two lukewarm beers out of her purse—pilfered from her dad—and we drink till we’re full, buoyant, barely tethered to the sand.

The United States experiences the worst heat wave since the Dust Bowl. Areas of Texas and Oklahoma report more than 40 days with high temperatures over 100 degrees. Crops and animals die in the ensuing drought.

The spacecraft Ulysses hurtles through space on its mission to collect data on solar wind. It resembles a satellite dish mashed together with a robot spider, all spiky legs and rounded plate. Ulysses tumbles right into a trail of debris, and its sensors alert scientists to the fact that it has glided through the tail of a comet. To everyone’s delight, Ulysses has bumped into a familiar face—Comet Hyakutake. This crossing of paths is less likely, says NASA’s Edward Smith, than “someone breaking the bank at Monte Carlo.” And yet it happens, the two trajectories intersect, lonely objects meeting, improbably, in the dark of space.


The samples I study are long, pencil-thin cross-sections retrieved by pushing a metal corer into a tree. Back in the lab they are shaved down and mounted on blocks, and when I slide my finger down the core and over the rings, I think about the years sliding by underneath the pad of my index finger, flowing centuries at a time, the wood growing older and older, gaining years and age before my very eyes.

I wanted there to be fireworks or something, I tell Alex. We are sitting in front of the lab computer, scrutinizing the output from a program that compares measurements from tree core samples and analyzes them to see if the measurements look to be accurate, or if any of the samples appear to have been misdated. The program, like many of the methods used in dendrochronology, is charmingly outdated. It does not tell us much: the sample could be 300 years off, it says. But the confidence quotient is so small. We conclude that, in fact, it does make sense, and confirm that I’ve measured and dated the sample correctly. Probably. It fills me with no satisfaction, and there’s no celebration, no fireworks or popped corks.

Tree-ring plot.
How to construct a skeleton plot, from An Introduction to Tree-Ring Dating.
Image courtesy The University of Arizona Press.


I am tempted to imbue coincidences with meaning and import. It’s hard not to want to make some kind of cosmic assumption about improbable intersections. To force events into a narrative that eases my existential stomachache, the motion sickness of moving through time and space with all the nonchalance of a finger traced down a slice of wood, like the gas corona around a comet pulled long into a brilliant tail by solar wind.


In 2018:

I watch the sky turn pale pink, then periwinkle, then indigo, tilt my face up and stare until the stars begin to flicker into view. I pick my way over rocks, my ankles in the cool running water, the cliffs of the canyon all around me, the saguaros nearly luminescent, tall spires, reaching fingers, towers. Recently transplanted to Arizona for grad school, I’ve taken myself far away from a city I loved and the people and structures that formed the scaffolding into which I poured myself.

I start volunteering in a lab that studies tree rings, desperate to recreate the conditions under which I’d written when I studied biology and literature in college. I want to write about trees. I see the effect of years of drought made manifest in once-living cells, touch the narrow rings that are 1996, 2003, and 2011, measure them, turn them into data.

I find myself scrolling through NASA’s website on Comet Hyakutake. The site looks like a relic from an earlier, kinder age of the internet. Tiled background and nearly unreadable font, tiny pixelated clipart of comets and space. It wrenches my heart to imagine the intrepid scientists typing these words, picking these images. And then I read, and as I do my eyes widen at the miracle of random chaos, the dates that seem to converge like magic with the ones I know so well from the lab: 1996, 2003, 2011.

I attempt to write about trees, and a comet, and my life. These threads converge in ways that I can’t fully account for, ways that are almost disturbing for the ease with which they collapse time and space—the leaps that disorient and leave me breathless, emotional, feeling both insignificant and connected.



Hea-Ream LeeHea-Ream Lee’s work has appeared in Popula, Hobart, the Hairpin, and others. She has received a fellowship from Bread Loaf Environmental Writer’s Conference and is working towards an MFA in creative nonfiction at the University of Arizona. She is writing a book about seed banks and longing. 

Header photo by Couleur, courtesy Pixabay. is the first online literary journal of place, publishing award-winning literature, art, editorials, and community case studies since 1998.